perf: parallelize mobile workspace fetch (Closes #1116)

src/frontend_bundle.py

@@ -114,7 +114,13 @@ def build_frontend(frontend_dir: Path) -> FrontendBuild:
         f'<meta name="stackchain-feature-{name}" content="{bundle.runtime_name}">'
         for name, bundle in feature_bundles.items()
     )
-    dashboard_html = dashboard_html.replace("</head>", feature_metadata + "\n</head>")
+    workspace_preload = (
+        f'<link rel="preload" as="script" '
+        f'href="{feature_bundles["today-timer"].runtime_name}">'
+    )
+    dashboard_html = dashboard_html.replace(
+        "</head>", feature_metadata + "\n" + workspace_preload + "\n</head>"
+    )
     dashboard_html = dashboard_html.replace(
         "</body>",
         f'<script src="{core.runtime_name}"></script>\n</body>',